第一关String类
package step1;import java.util.Scanner;public class StringLearning {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);String stringExample = scanner.next();String endStr = " end";// ---------------------Begin------------------------int len =stringExample.length();System.out.println("原字符串为："+stringExample);System.out.println("字符串长度为："+len);System.out.println("转换成大写字符串："+stringExample.toUpperCase());System.out.println("转换成小写字符串："+stringExample.toLowerCase());System.out.println("第3-7的字符串内容为："+stringExample.substring(3,7));System.out.println("字符串相加后:"+stringExample.concat(endStr));// ---------------------End------------------------}
}
第2关：StringBuffer类
package step2;import java.util.Scanner;public class StringBufferLearning {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);String stringExample = scanner.next();// ---------------------Begin------------------------StringBuffer sb1=new StringBuffer(stringExample+"educode");System.out.println("添加数据后："+sb1);sb1.delete(5,8);System.out.println("删除5-8的字符串后："+sb1);sb1.replace(7,13,"world");System.out.println("替换7-13的字符串后："+sb1);System.out.println("截取1-10的字符串为："+sb1.substring(1,10));sb1.reverse();System.out.println("反转后的字符串为："+sb1);// ---------------------End------------------------}
}
第3关：Math类
package step3;import java.util.Scanner;public class MathClass {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);int value1 = scanner.nextInt();int value2 = scanner.nextInt();// ---------------------Begin------------------------/**1.求出变量value1的绝对值2.求出value1的3次幂3.求出value1的二次方根4.求出value1的sin值5.求出value1与value2中的较大者* */System.out.println("value1="+value1+", "+"value2="+value2);int n=Math.abs(value1); System.out.println("value1的绝对值为："+Math.abs(value1));double n1=Math.pow(value1,3);System.out.println("value1的3次幂为："+String.format("%.6f",n1));double n2=Math.sqrt(value1);System.out.println("value1的2次方根为："+String.format("%.6f",n2));double n3=Math.sin(value1);System.out.println("value1的sin值为："+String.format("%.6f",n3));System.out.println("value1与value2中的较大者为："+Math.max(value1,value2));// ---------------------End------------------------}
}
第4关：Random类
package step4;import java.util.Random;public class RandomClass {public static void main(String[] args) {// ---------------------Begin------------------------Random r = new Random(2022); // 不传入种子// 随机产生10个[0,100)之间的整数for (int x = 0; x < 5; x++) {System.out.println(r.nextInt());}for (int x = 0; x < 5; x++) {System.out.println(r.nextDouble());}// ---------------------End------------------------}
}
第5关：知识回顾
1D 2 正确 3 正确 4StringBuffer
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